SNAA320B November   2019  – January 2024 LM4040-N , LM4050-N , LM4128 , LM4128-Q1 , LM4132 , LM4132-Q1 , REF102 , REF1925 , REF1930 , REF1933 , REF1941 , REF20-Q1 , REF200 , REF2025 , REF2030 , REF2033 , REF2041 , REF2125 , REF2912 , REF2920 , REF2925 , REF2930 , REF2933 , REF2940 , REF3012 , REF3020 , REF3025 , REF3030 , REF3033 , REF3033-Q1 , REF31-Q1 , REF3112 , REF3120 , REF3125 , REF3130 , REF3133 , REF3140 , REF3212 , REF3212-EP , REF3220 , REF3220-EP , REF3225 , REF3225-EP , REF3230 , REF3230-EP , REF3233 , REF3240 , REF3312 , REF3318 , REF3320 , REF3325 , REF3330 , REF3333 , REF34-Q1 , REF3425 , REF3425-EP , REF3430 , REF3430-EP , REF3433 , REF3433-EP , REF3440 , REF3440-EP , REF3450 , REF35 , REF4132 , REF4132-Q1 , REF5010 , REF5020 , REF5020-EP , REF5020A-Q1 , REF5025 , REF5025-EP , REF5025-HT , REF5025A-Q1 , REF5030 , REF5030A-Q1 , REF5040 , REF5040-EP , REF5040A-Q1 , REF5045 , REF5045A-Q1 , REF5050 , REF5050-EP , REF5050A-Q1 , REF54 , REF6125 , REF6133 , REF6141 , REF6145 , REF6150 , REF6225 , REF6230 , REF6233 , REF6241 , REF6245 , REF6250 , REF70 , TL431LI , TL432LI , TLV431

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1 Introduction
  5. 2 Analog-to-Digital Converter Error
  6. 3 Voltage Reference DC Error
    1. 3.1 Initial Accuracy and Solder Shift
    2. 3.2 Temperature Drift
    3. 3.3 Line Regulation
  7. 4 DC Error Calculations
  8. 5 Calibration
  9. 6 Voltage Reference Noise Error
    1. 6.1 1/f Noise
    2. 6.2 Broadband Noise
    3. 6.3 Power Supply Rejection Ratio
    4. 6.4 Noise Example
  10. 7 Dynamic Error (Voltage Reference Driving Capability)
  11. 8 Low Power Applications
  12. 9 References
  13. 10Revision History

8 Low Power Applications

In low-power high-accuracy designs, limiting the IQ for each component of a signal chain while not degrading the performance of the design is critical. A generic signal chain, usually have components like sensors, amplifiers, converters, micro controllers, voltage references, interfaces, and so on; which contribute to the overall current budget of the design. Hence to reduce the power consumption of the design,choose components that operate at lower quiescent current.

Field Transmitter is one such example of a low IQ design where current contribution from each component can affect the power budget of the system. Typical power budget for a field transmitter is shown in Figure 8-1.

GUID-20230807-SS0I-V2SN-M7C8-H82DM0MZ9MKT-low.svg Figure 8-1 Typical Power Budget of a Field Transmitter

Figure 8-1 shows that the current contribution from REF35 voltage reference IC is just 0.02% of the total current budget (3mA typical for a 2-wire transmitter), hence choosing REF35 does not burden the total current budget heavily. Although REF35 operates at a very low (650nA) quiescent current, REF35 does not compromise with the series reference specs. REF35 provides very high initial accuracy (0.05%), very low temperature drift (12ppm/C) and very low inherent noise.

Furthermore, REF35 has Shutdown Mode which is an additional feature. This feature can be enabled to reduce the quiescent current of the device to less than 0.1uA by pulling down the enable pin on the IC. This helps to bring down the overall power consumption of the signal chain in the standby mode.

Therefore, in low power high accuracy designs where the system specs cannot be compromised, choosing right voltage reference for high precision ADCs becomes very important. Hence selecting a reference like REF35 enables designers to develop low power designs without sacrificing with the accuracy.